1. Technical Field
The present invention relates to an ultrasonic sensor and a method for producing the ultrasonic sensor.
2. Related Art
There has been known an ultrasonic sensor which includes: a semiconductor substrate having openings; and elements each of which is constituted by two layers of electrodes on an insulation layer provided on a surface of the semiconductor substrate so as to close the opening and a thin PZT ceramic layer sandwiched between the electrodes, and which are arranged in an array (for example, refer to JP-A-2010-164331).
In such an ultrasonic sensor in which the elements are arranged in an array, in order for first electrodes and second electrodes to be led out of the elements, particularly, in order for the second electrodes to be led out of the elements, it is necessary that the electrodes be common to the elements. However, if an active part is provided in an area other than the openings, sending and receiving cannot be carried out efficiently, and this leads to decreased reliability.